The goal of this project is to provide support of National Toxicology Program (NTP) researching the potential adverse effect of botanical dietary supplements. Botanical dietary supplement research has several challenges including identifying the active ingredients to link them to observed outcomes due to complex makeup of the mixtures. Proper chemical analyses are required to ensure that, in toxicity studies, the test species are exposed to the test articles at the specified dose concentrations. This contract characterizes the chemical and physical composition of the botanical dietary supplements studied in the testing program. This information is critical to evaluation of toxicity tests and development of sound, scientific conclusions about the potential toxicity of the study chemical in the test species and ultimately supports the risk assessment efforts of the National Toxicology Program and other federal agencies. In addition, this contract also provides chemistry support for in vitro testing in multiple animal and human cell lines of a wide variety of chemicals of public health concern.